Sodium container



Oct. 15, 1957 E. R. CORNEIL SODIUM CONTAINER Filed June 30, 1955INVENTOR. Erna/5+ R. Cornefl United States Patent SODIUM CONTAINERErnest R. Corneil, Thorold, Ontario, Canada, assignor to E. I. du Pontde Nemours and Company, Wilmington, Del., a corporation of DelawareApplication June 30, 1955, Serial No. 519,089

3 Claims. (Cl. 206-84) This application relates to a container forstoring and shipping metallic sodium and is a continuation-in-part of mycopending application Serial Number 311,939, filed September 27, 1952,and issued as U. S. Patent 2,712,384 on July 5, 1955.

Unlike most metals of commerce sodium is extremely reactive towards theoxygen of the atmosphere. When this element is stored or shipped, itmust, therefore, be kept from contact with air. Closed containers areusually adopted to minimize the undesired contact. Since it melts ataround 97.5 0, sodium may readily be melted and transferred to thecontainer in the liquid state. Facilities are generally available at thepackaging shop or warehouse to handle molten sodium. Similar facilitiesfrequently do not exist at the point of use of the material. Inaddition, experience indicates that the melting process is slow althoughthe proper equipment is at hand. A container from which metallic sodiumcan easily be removed in the solid state is, therefore, greatly desired.

A general object of the present invention is, consequently, provision ofimprovements in the packaging of sodium.

A further object is provision of a sodium package from which the metalcan be easily removed in the solid state.

The above-mentioned and yet other objects are achieved in accordancewith this invention by placing liquid sodium in a specially prepareddrum which can be opened at its center, sealing the drum and allowingthe liquid to freeze. The shrinkage of the sodium upon freezing createsa small region in the closed drum above the sodium free both of air andof metal. The sodium is thus in effect vacuumpacked and sealed off fromcontact with the atmosphere.

Details of preferred embodiments of the invention will be evident fromthe drawings, in which:

Figure 1 is a longitudinal section of a sealed drum containingvacuum-packed sodium;

Figure 2 is an en argement of part of Figure 1 at the mid-section of thedrum to show the method of joining the two halves thereof;

Figure 3 is a plan view showing a preferred method of closing theresilient metallic belt holding the halves of the drum together; and

Figure 4 is an enlargement of part of the section of Figure 1 showingthe rough nature of the interior surface of the drum in one embodimentthereof.

In Figure 1 is seen a drumformed of two substantially identical sections11 and 12 held together, when assembled, by steel belt or band 13. Eachof the identical sections is provided with a hoop, 14 or 15, as the casemay be, to facilitate rolling the barrel in transit. Each section ispreferably provided with a bung 16 although only one is shown. Withindrum 10 is a body of solid sodium 17 which has shrunk in cooling toleave a vacuum space 18 at the top of the drum.

As noted above, the drum is preferably formed of two identical halves.Each half should be tapered from an open end to a fiat closed bottomcontaining a bung and,

if desired, a vent for use while the barrel is being filled. The taperfacilitates easy removal of solid sodium from the barrel halves. Apreferred form for each half is frusto-conical although other taperedforms may be used as well. The bung can, of course, be omittedaltogether from one of the halves. Other minor differences between thesections can be tolerated as long as the two possess the same diameterat the respective open ends. If, however, the two sections areidentical, there is complete interchangeability of parts and assembly ofthe complete drum is very simple.

The method of closing the assembled drum at its midsection is best seenin Figure 2. Sections 11 and 12 terminate in chimes 19 and 20respectively. Within the chimes are preferably positioned steelstrengthening rings 21 and 22 although these can be omitted. The chimesof the two sections are seated in the symmetrical gasket 23 whichextends completely around the barrel at its greatest diameter.Preferably the gasket possesses the cross-section of the letter H andmay, therefore, be referred to as an H-gasket. The gasket should beresilient in nature and may be formed from rubber or other resilientmaterial substantially nonreactive to metallic sodium.

Snugly fitting around the outside of the chimes as shown in Figures 1and 2 is steel belt 13. This belt should be just large enough to extendcompletely around the barrel and strong enough to effect closure underthe most severe conditions of shock to which the barrel may besubjected. The cross-section of the belt should be that of a symmetricalcapital (3 for ease in encompassing the chimes. The belt should alsopossess some resiliency enabling it to be easily positioned lengthwisearound the barrel and in breadth, i. e., across the C-section, aroundthe chimes. A preferred material of construction for the belt is steelalthough other materials having the necessary strength and resiliencycan also be used.

A preferred method of joining the two ends of the belt is shown inFigure 3. Projecting lugs 24 are Welded or otherwise united with thebelt at the ends. These have holes through which bolts 25 can beinserted and tightened as desired or necessary. It will be noted thatdisposition of the bolts on the ends of the C of the cross-sectionpermits the belt to be tightened both in length and in width around thechimes.

The method of assembling the barrel is evident from the descriptiongiven. Upon the chime of one of the identical sections is first placedthe H-gasket. The chime of the section is then placed in the unoccupiedside of the gasket. The belt is then slipped around the chimes and theends of the belt joined.

The method of filling the assembled barrel with sodium will also beevident from the description above. The barrel is stood on end and oneof the bungs is opened. The barrel is then flushed with nitrogen,helium, argon or other inert gas and liquid sodium run thereinto. Whenthe barrel is full and while the sodium is still liquid, the open bungis closed. As the sodium cools it shrinks and creates the vacuum at thetop of the barrel. The pressure of the air forces the top section of thebarrel further into the gasket and contributes to the closure at themidsection. It may, in fact, be necessary to tighten the bolts at thebelt for a second time after the sodium has cooled. The sodium is,however, vacuum-packed and free from contact with oxygen, carbondioxide, water vapor or other reactive gases.

in addition to its reactivity towards the atmosphere and its low meltingpoint, sodium possesses another property of great importance withrespect to its packaging. This property is its tendency to wet andadhere to or even to react with the majority of materials ofconstruction it contacts. Parent application 311,939 discusses theadherence of sodium to other materials at length and the disclosure ofthat application is accordingly incorporated by reference herein.

T The adherence of sodium to other materials, of course, raises a majorproblem with respectto the container of the present invention. If thebarrel is of a common material such as steel or aluminum and prepared inthe normal manner the sodium could' not directly be pulled therefrom. Itthus would be impossible to open the barrel at itscenter and remove thesodium as a solid. Some treatment. of the inner surface of the barrelis, therefore, essential. v

The treatment of the parent application can be used if it is so desired.That is, the container can be lined with solid polyethylene, asubstancetowards which sodium is essentially passive. Insertion of thepolyethylene lining, however, introduces a large quantity of a thirdmaterial into the containerand additional complications into filling thesame and is, for that reason, not preferred.

It has now been found that some metallic surfaces to which sodiumnormally adheres can be made nonadherent in another manner. Thisalternative, and preferred, treatment consists basically of renderingthe surface very rough by forming many small or microscopic porestherein. Sodium does not adhere to such a surface even when frozen incontact therewith. This result is quite surprising since smooth surfacesare frequently roughened to increase the adherence of various materials,paints especially. The pores can be filled with oil, if it is sodesired. The oil, however, is unnecessary and is actually less preferredsince it also introduces an additional step into the process and maysoil or contaminate the sodium.

Surfaces suitably roughened to avoid adherence to sodium can be preparedin a variety of ways. One way is by phosphatizing the base metal by anyof the methods shown, for example, in U. S. Patent 2,515,934. Thus thinphosphatized layers containing many microscopic pores can be formed onsuch metals as steel, zinc and cast iron by dipping the metal in orspraying it with a hot aqueous solution containing phosphoric acid.

Aluminum cannot readily be phosphatized. It is found, however, thatanodizing this metal by conventional methods produces a surfacenonadherent to sodium. The anodization of aluminum can readily beaccomplished by passing an electric current from a cathode to thealuminum article or anode through an aqueous solution of sulfuric,chromic, oxalic, boric or like acids.

Figure 4 illustrates an enlargement of a metallic surface 26 nonadherentto sodium. In its preferred embodiment the barrel should possess such asurface, the metal of the wall being roughened to contain manymicroscopic pores. In this manner iron, steel. and aluminum can readilybe adapted for use with sodium.

Various advantages of my invention will be evident from thespecification. Generally these advantages parallel the objects but somemay be specifically mentioned. Thus forming the container in twoidentical halves facilitates manufacture and assembly thereof.Furthermore, the use of curved surfaces in the halves is a source ofstrength not interfering with 'the' easy removal of the sodium in thesolid state. Use of the center opening permits this easy removal. Thenecessity of corrugations or rolled hoops, clearly undesirable withmalleable sodium, is concomitantly eliminated by these curved surfaces.In addition, an unlined container has been provided which does notadhere to sodium.

It will be appreciated that various minor changes can be made in thecontainer described without departing from the spirit of the invention.Thus the configuration of the halves of the container can be alteredwithin wide limits as long as nothing interfering with the free removalof the sodium is introduced. Consequently I propose to be bound solelyby the appended claims.

Having described my invention, I claim:

1. An article of manufacture comprising a ferrous metal container, aphosphatized surface integral with the inner Wall of said container, andmetallic sodium disposed within the container, the phosphatized surfacepreventing the adhesion of the sodium to the ferrous metal. 7

2. The invention of claim 1 in which the container is formed of steel.

3. The invention of claim 1 in which the container is formed of castiron.

References Cited in the file of this patent UNITED STATES PATENTS429,660 Sullivan June 10, 1890 704,366 Phillips July 8, 1902 966,513Avery Aug. 9, 1910 1,734,189 Young Nov. 5, 1929 2,310,239 Jernstedt Feb.9, 1943 2,412,024 Young Dec. 3, 1946 2,515,934 Verner July 18, 19502,683,113 Prance July 6, 1954 2,712,384 Corneil July 5, 1955 2,724,526Russell Nov. 22, 1955

1. AN ARTICLE OF MANUFACTURE COMPRISING A FERROUS METAL CONTAINER, APHOSPHATIZED SURFACE INTEGRAL WITH THE INNER WALL OF SAID CONTAINER, ANDMETALLIC SODIUM DISPOSED WITHIN THE CONTAINER, THE PHOSPHATIZED SURFACEPREVENTING THE ADHESION OF THE SODIUM TO THE FERROUS METAL.